Method and device for regulating the temperature of a coolant of an internal combustion engine

ABSTRACT

A method for regulating the temperature of a coolant of an internal combustion engine, including a temperature sensor detecting the temperature of the coolant and a first control unit controlling and/or regulating the coolant temperature to obtain a predetermined temperature setpoint value, a further control unit being provided whose signals are fed to the first control unit, the further control unit relaying signals about an established driver type to the first control unit and, depending on whether the driver type is classified as sporty or economical, the first control unit presetting the temperature setpoint value, in which a coolant volume flow for cooling the internal combustion engine is regulated or controlled by the control unit as a function of the driver type established.

FIELD OF THE INVENTION

The present invention relates to a method for regulating the temperatureof a coolant of an internal combustion engine, a temperature sensordetecting the temperature of the coolant and a first control unitcontrolling and/or regulating the coolant temperature in order to obtaina predetermined temperature setpoint value, a further control unit beingprovided whose signals are fed to the first control unit, the furthercontrol unit relaying signals about an established driver type of themotor vehicle to the first control unit and, depending on whether thedriver type is classified as economical or sporty, the first controlunit presetting the temperature setpoint value.

Furthermore, the present invention relates to a device, such as for amotor vehicle having an internal combustion engine and a cooling device,including a control unit for controlling and/or regulating a setpointtemperature value of a coolant, and a temperature sensor for measuringthe actual temperature value, and a valve for setting a coolant volumeflow to a radiator and/or to the internal combustion engine, a secondcontrol unit being provided which works together with the first controlunit in order to relay information in regard to the driver type,including a sporty or economical driver type, to the first control unitand, on the basis of this information, a temperature setpoint valuebeing determinable by the first control unit.

BACKGROUND INFORMATION

German Published Patent Application No. 199 51 362 discusses a methodfor regulating the cooling water temperature, a temperature sensordetecting the cooling water temperature and a control unit for thecooling water temperature actuating at least one valve and/or one fan inorder to obtain a predetermined temperature setpoint value of thecooling water, a further sensor and/or an engine or vehicle control unitbeing provided whose signals are fed to the first control unit, thefirst control unit determining a temperature setpoint value therefrom.The determination of the setpoint value may be predetermined as afunction of the driver type, a driver who drives sportily oreconomically, for example.

In this manner, the exhaust gas value and the fuel consumption may beoptimized and/or minimized.

Furthermore, German Published Patent Application No. 41 09 498 discussesregulating the temperature of an internal combustion engine so thatdifferent temperature setpoint value ranges are used for the temperatureregulation on the basis of different operating conditions. Inparticular, operating parameters of the internal combustion engine,among other things switching on of auxiliary systems and malfunctions ofthe internal combustion engine, may be cited as operating conditions.The setpoint value of the cooling water temperature may be set dependingon which priority the different operating conditions have.

SUMMARY OF THE INVENTION

The present invention relates to an exemplary method and an exemplarydevice for regulating the temperature of an internal combustion engineto reduce the fuel consumption further, including, for example, for aneconomical driver, without performance losses being noticeable for asporty driver, and to reduce the emissions overall.

The present invention may provide an exemplary method and/or device inwhich the volume flow of the coolant for cooling the internal combustionengine is regulated and/or controlled by the control unit as a functionof the driver type established.

The efficiency of an internal combustion engine cooled using a coolantmay be increased in the part-load range if the temperature of thiscoolant is elevated above the currently mostly set value of 95° Celsius,to a range of 105°–115° Celsius. In the full-load range, however, thetemperature of the coolant may be required to be lowered again in orderto limit damage to the internal combustion engine and/or performancelosses. An exemplary method thus may provide temperature regulation ofthe engine using higher temperatures in part-load operation and lowertemperatures in full-load operation, using which the problem of knockingand/or performance losses in the transition from part-load to full-loadoperation may be minimized.

The driver type may be included in the operating parameters which theexemplary method may use for control. According to an exemplary methodfor determining the driver type, a sporty driver type may be determinedif frequent and rapid load changes are performed and an economicaldriver type may be concluded in the event of infrequent and slow loadchanges.

If the quantity of the coolant that flows to the internal combustionengine, i.e., the coolant volume flow, is also made a function of thedriver type, the danger of local overheating at especially hot points ofthe cylinder head, which may arise in the event of a strong and suddenelevation of the engine load, for example, may also be avoided still.

In this instance, for example, the exemplary method may assign arelatively low coolant volume flow to an economical driver type, suchas, for example, in part-load operation. Thus, little energy may berequired for circulating the coolant and the desired temperature may beachieved more rapidly even in the warmup phase of the engine. Bothparameters may have a desired effect on the fuel consumption.

If a rapid and strong load elevation nonetheless occurs, a highercoolant volume flow may be required to be first achieved before thecoolant may dissipate the waste heat of the engine, which may now bestrongly increased. Therefore, if it is to be expected that rapid andstrong load elevations will occur, since, for example, the driver typeis rather sporty, the exemplary method may initially assign this drivertype a higher coolant volume flow than an economical driver type (evenin part-load operation). Therefore, if a rapid and strong load elevationoccurs, a volume flow sufficient to reliably dissipate the waste heatmay be immediately available. A higher coolant volume flow of this typeand therefore also an elevated fuel consumption may be more acceptablefor a sporty driver.

Furthermore, the coolant temperature may be controlled and/or regulatedbetween an upper and a lower limiting value by the control unit. Inparticular, 95° Celsius may be used as the lower limiting value, and avalue between 105 and 115° Celsius may be used as the upper limitingvalue.

In this instance, it may be provided that temperatures outside thesetemperature limits are not approached.

For the determination of the driver type, only a selection between aneconomical and a sporty driver type may be provided. However,intermediate values may also be fixed, these values being determinablecontinuously or in discrete steps. Intermediate values may then also beset between the two limiting values previously cited in this instance.For this purpose, a digital selector switch between “sporty” and“economical” may thus be provided. However, the selector switch may alsoapproach multiple intermediate steps.

According to a first exemplary embodiment, the coolant temperature maylie closer to the upper limiting value the more the driver type isclassified as the economical driver type. In this instance, such as inpart-load operation, a higher cooling water temperature may be set forthe economical driver type than for the sporty driver type. Forintermediate values, the coolant temperature may be set lower the closerthis intermediate value is to the sporty driver type. The exemplarymethod may provide a desired result when it is implemented forpart-load. The exemplary method according to the present invention maythus assign a lower coolant temperature setpoint value to a sportydriver type than to an economical driver type, even for part-loadoperation of the engine. The coolant temperature may thus be closer tothe lower limiting value, such as in part-load operation, the more thedriver type is classified as the sporty driver type. In this manner, fora sporty driver type, the danger of performance loss upon changing frompart-load operation to full-load operation is lower, even if this is atthe price of elevated fuel consumption. Because of the elevated coolanttemperature in part-load operation, the economical driver type mayachieve lower fuel consumption, which may be, however, connected with ahigher risk of performance loss in the transition from part-loadoperation to full-load operation. In this instance, even for theeconomical driver type, a shift in the direction of the upper limitingvalue may only be provided when the internal combustion engine isoperated in part-load operation.

For example, for the sporty driver type, no shift in the direction ofthe upper limiting value may occur, even for part-load operation of theinternal combustion engine. It may be more acceptable for a sportydriver type to tolerate this lower cooling water temperature andtherefore the elevated fuel consumption, instead of the performanceloss.

For example, in the exemplary method according to the present inventionit may be provided that the sporty driver is assigned a higher coolantflow, at least in part-load operation, than the economical driver type.Because of this assignment, the danger of local overheating atespecially hot points in the cylinder head, as may otherwise arise inthe event of a strong and rapid increase of the engine load, may bereduced for a sporty driver. However, an elevated fuel consumption maybe achieved, since more coolant may be circulated.

The economical driver type may be assigned a lower coolant volume flowonly in part-load operation, and the coolant flow for the sporty and theeconomical drivers may be identical in full-load operation.

For example, there may be no adaptation of the coolant volume flow forthe sporty driver type even in part-load operation, i.e., the coolantvolume flow for the sporty driver may always be equally high.

In this manner, performance losses and the danger of overheating of theengine may be prevented better.

In addition, an exemplary embodiment of the present invention may relateto a control unit of an internal combustion engine, such as, forexample, for a motor vehicle, on which a program may be stored, whichmay be executable on a computing device, including, for example, amicroprocessor, and may be capable of executing an exemplary method asdescribed above.

Furthermore, the present invention may relate to an exemplary device fora motor vehicle having an internal combustion engine, whereby theinternal combustion engine may include a control and/or regulating unitas described above.

The control unit which may be used as the second control unit may be theelectronic engine control unit.

Further advantages and features of the present invention may result fromthe remaining documents of the application. The features may beessential for the present invention individually or in any arbitrarycombination with one another.

In the following, the present invention is to be described in greaterdetail on the basis of an exemplary embodiment. The exemplary embodimentis illustrated in the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a schematic circuit diagram of an exemplary cooling circuitof an internal combustion engine.

DETAILED DESCRIPTION

The internal combustion engine includes an internal combustion engine 10and a coolant pump 12, which may pump the coolant through a coolingcircuit for cooling internal combustion engine 10. In this instance,coolant pump 12 may either be driven directly by the crankshaft ofinternal combustion engine 10 via a belt or it may be an electricallydriven coolant pump.

Coolant pump 12 is connected to a device for varying coolant volume flow14. In particular, if coolant pump 12 is an electrical coolant pump, thevariation of the volume flow may be simple to perform.

Via a coolant line 16, either all or part of the coolant may flow via aradiator 18 and thus may be cooled.

Via a thermostat valve 20 and a bypass line 22, coolant may flow pastradiator 18. A bypass line 22 of this type may optionally be provided.

Via a further coolant line 24, coolant from internal combustion engine10 is conducted from the internal combustion engine via a heater heatexchanger 26 to coolant pump 12. A passenger compartment may be heatedvia heater heat exchanger 26, for example.

In this instance, thermostat valve 20 may be actuated by an electronicfirst control unit 30 via an actuator 28. Depending on the position ofvalve 20, a larger or smaller part of the coolant volume flow flows viaradiator 18 and is cooled. By mixing coolant which was cooled via theradiator and coolant which flows via bypass line 22 and/or heater heatexchanger 26, the temperature of the coolant at the intake of internalcombustion engine 10 may be set by electronic control unit 30.

In addition, at least one temperature sensor 32 may be provided in thecooling circuit, via which control unit 30 may determine the temperatureof the coolant, i.e., the actual temperature.

In addition, a second electronic control unit 34 may be provided, whichmay be the engine control unit in this instance. This second controlunit 34 determines a driver type in the range between economical andsporty from an available related method, such as, for example, fortransmission control. In this instance, a finite number of intermediatevalues, which may also be set, may be provided between these two values.Control unit 34 analyzes the position of a selector switch (not shown)for this purpose.

Second electronic control unit 34 has a data link to first electroniccontrol unit 30, via a CAN bus, for example, in this instance.

Alternatively, the first and the second control unit may also beimplemented in one single control unit.

To reduce the fuel consumption, improve the emissions, and nonethelessobtain a satisfactory performance distribution, and to reduce thetendency to knock, the coolant temperature may be influenced dependingon whether the driver is sporty or economical.

For this purpose, a corresponding control program for performing anexemplary method according to the present invention may be stored incontrol unit 30. Through the exemplary method, valve 20 is opened andclosed via actuator 28. By changing the position of valve 20, thetemperature of the coolant may be varied, since the flow of the coolantwhich flows via radiator 18 may be varied in this manner. In thisinstance, besides the other operating parameters of the internalcombustion engine, the control program may also take the driver typedetermined in control unit 34 into consideration. The control program incontrol unit 30 actuates valve 20 via actuator 28 in this instance sothat, at least for some values of the operating parameters of theinternal combustion engine, a different, such as, for example, a lowervalue of the coolant temperature may be set for a sporty driver typethan for an economical driver type. If there is an intermediate value ofthe driver type between “sporty” and “economical,” the coolanttemperature may be set lower for this intermediate value of the drivertype the closer this intermediate value is to the driver type “sporty.”

For example, a lower value of the coolant temperature may be set for asporty driver than for an economical driver for the operating parameter“part-load” of the internal combustion engine. For intermediate values,the statement above may apply. For example, it may be provided that fora sporty driver, also for part-load operation, no higher value of thecoolant temperature may be set than is the case for full-load, while foran economical driver type a higher value of the coolant temperature maybe set for part-load than is the case for full-load. Thus, for example,for an economical driver type, the temperature in part-load operationmay be raised to 105°–115° Celsius as the upper limiting value and thecoolant temperature may only be reduced to 95° Celsius in full-loadoperation in order to limit damage to the internal combustion engineand/or performance losses. However, the efficiency of internalcombustion engine 10 may be increased by increasing the coolanttemperature.

In addition, according to an exemplary embodiment of the presentinvention, besides varying the coolant temperature as a function of thedriver type, the volume flow of the coolant may also be varied bycontrol unit 30 via device 14 as a function of the driver type. In thisinstance, the control program in control unit 30 may assign a relativelylow coolant volume flow to an economical driver type, such as, forexample, in part-load operation. Thus, little energy may be required forcirculating the coolant and the engine may reach the desired temperaturemore rapidly in the warmup phase. A lower fuel consumption may thus beachieved.

If rapid and strong load elevation occurs, however, a higher coolantvolume flow may be required to be first achieved before the coolant maydissipate the waste heat of the engine, which may be now stronglyincreased. Therefore, the control program in control unit 30 assigns ahigher coolant volume flow to a sporty driver, such as, for example, inpart-load operation, than to an economical driver type. In this manner,a sufficient coolant flow to ensure heat dissipation reliably andprevent damage to internal combustion engine 10 may be available for asporty driver type. Since a sporty driver type may be distinguished byfrequent and rapid load changes, the elevated coolant volume flow ofthis type may be appropriate. The elevated fuel consumption connectedtherewith may be accepted. For example, for the sporty driver, even forpart-load, a lower value of the coolant quantity than is the case forfull-load may not be set.

For intermediate values of the driver type which lie between “sporty”and “economical,” the volume flow may be set lower for identical loadthe closer the driver type lies to economical.

The driver type may be determined, for example, in that a sporty drivertype is concluded in the event of frequent and rapid load changes and aneconomical driver type may be concluded in the event of infrequent andslow load changes.

1. A method for regulating a temperature of a coolant of an internalcombustion engine, comprising: detecting, by a temperature sensor, atemperature of the coolant; at least one of controlling and regulating,by a first control unit, the coolant temperature to obtain apredetermined temperature setpoint value; one of feeding and relayingsignals of a further control unit about an established driver type tothe first control unit; presetting, by the first control unit, thetemperature setpoint value, depending on whether the established drivertype is classified as one of a sporty driver type and an economicaldriver type; and one of regulating and controlling, by the first controlunit, a coolant volume flow for cooling the internal combustion engineas a function of the established driver type.
 2. The method of claim 1,wherein at least one of the coolant temperature and the coolant volumeflow is at least one of controlled and regulated between an upper and alower limiting value by the first control unit.
 3. The method of claim1, wherein the driver type is one of an arbitrary setting and a discreteintermediate setting between the sporty driver type and the economicaldriver type.
 4. The method of claim 2, wherein the coolant temperaturelies closer to the upper limiting value the more the established drivertype is classified as the economical driver type.
 5. The method of claim2, wherein the coolant temperature lies closer to the lower limitingvalue the more the established driver type is classified as the sportydriver type.
 6. The method of claim 2, further comprising: only shiftingthe temperature setpoint value in a direction of the upper limitingvalue if the internal combustion engine is operated in part-loadoperation.
 7. The method of claim 2, wherein for the sporty driver type,the temperature setpoint value is not shifted in a direction of theupper limiting value even in the event of part-load operation of theinternal combustion engine.
 8. The method of claim 1, wherein for theeconomical driver type, a lower coolant volume flow is set at least inpart-load operation than for full-load operation.
 9. The method of claim1, wherein, at least in part-load operation, a higher coolant volumeflow is set for the sporty driver type than for the economical drivertype.
 10. The method of claim 1, wherein a lower coolant volume flow inpart-load operation than for full-load operation is not set for thesporty driver type.
 11. A control unit of an internal combustion engine,on which a program is stored, which is executable on a computing deviceand capable of executing the steps of: detecting, by a temperaturesensor, a temperature of the coolant; at least one of controlling andregulating, by a first control unit, the coolant temperature to obtain apredetermined temperature setpoint value; one of feeding and relayingsignals of a further control unit about an established driver type tothe first control unit; presetting, by the first control unit, thetemperature setpoint value, depending on whether the established drivertype is classified as one of a sporty driver type and an economicaldriver type; and one of regulating and controlling, by the first controlunit, a coolant volume flow for cooling the internal combustion engineas a function of the established driver type.
 12. The control unit ofclaim 11, wherein the control unit is operable for an internalcombustion engine of a motor vehicle.
 13. The control unit of claim 11,wherein the computing device includes a microprocessor.
 14. A device,comprising: an internal combustion engine; a cooling device including: adevice to set a coolant volume flow to at least one of a radiator andthe internal combustion engine; a temperature sensor to measure anactual temperature value; a first control unit to, on a basis of aspecified driver type, determine a temperature setpoint value of acoolant, at least one of control and regulate the setpoint temperaturevalue, and vary the coolant volume flow; and a second control unit towork together with the first control unit to specify the driver type,wherein the specified driver type is one of a sporty driver type, aneconomical driver type, and an intermediate value.
 15. The device ofclaim 14, wherein the device is operable in a motor vehicle.
 16. Thedevice of claim 14, further comprising: a radiator; a bypass line; and avalve to control a coolant volume flow via at least one of the radiatorand the bypass line, depending on a temperature to be set.
 17. Thedevice of claim 14, wherein the second control unit includes anelectronic engine control unit.
 18. The device of claim 14, furthercomprising: a coolant pump to circulating the coolant volume flow. 19.The device of claim 18, wherein the coolant pump includes an electroniccoolant pump.
 20. The device of claim 14, wherein the first and secondcontrol units are arranged as a single control unit.
 21. The device ofclaim 14, wherein the control unit includes a stored program and acomputing device to execute the stored program to perform the operationsof the first and second control units.